Potential Anticancer Activities and Catalytic Oxidation Efficiency of Platinum(IV) Complex

The treatment of an aqueous acetonitrile solution of chloroplatinic acid hydrate H₂PtCl₆.xH₂O and pyridine-2-carbaldehyde-oxime (paOH) in the presence of potassium thiocyanate at room temperature (25°) led to the formation of a new Pt(IV) complex with the formula [Pt(SCN)₂(paO)₂], (1). Complex 1 was fully characterized by FT-IR, UV-vis and NMR spectroscopic techniques as well as elemental analysis. The crystallographic structure of complex 1 was obtained by single-crystal X-ray diffraction. The structure of complex 1 consists of a distorted octahedral geometrical environment around the platinum center in which the coordination sites are occupied by two terminal thiocyanate ligands in trans arrangement and two bidentate paO ligands through four nitrogen atoms. In addition, the in vitro evaluation of the cytotoxicity of platinum complex 1 against four different cancer cell lines was performed. The IC₅₀ values for colon (HCT116), liver (HepG2), breast (MCF-7) and erythroid (JK-1) treated with complex 1 are 19 ± 6, 21 ± 5, 22 ± 6, and 13 ± 3 μM, respectively. In HCT116 cells treated with the IC50 dose of our title compound, apoptosis and necrosis were increased by 34% and 27.8%, respectively. Cells halted in the proliferative phase (S phase) to 21.7 % and 29.8% in HCT116 and HepG2 cells treated with complex 1 have anti-proliferative actions. Furthermore, the catalytic activity of synthesized complex 1 was examined in the oxidation reaction of benzyl alcohols in the presence of an oxidant. Finally, the luminescence behavior of complex 1 was investigated.     

密度泛函理论方法研究双核铜化合物的磁性和自旋密度分布

Magnetic coupling constants J between Cu ions and spin density map for a binuclear complex Cu₂(2,2′-bpy)₂(4,4′-bpy)₂L₂ have been calculated by the combination of the broken symmetry approach with the spin project method under the DFT framework and the effect of nonorthogonality between magnetic α and β orbitals in the broken symmetry solution. The result indicates that using SV/SVP basis sets in the calculation of Gaussian 98 is much better than using LanL2DZ pseudo-potential function in above system. It is interesting that calculated J value is quite near to the experimental value in the studies of magnetic susceptibility.     

Crystal Structure and Density Functional Theory Studies of （p-Methoxyphenyl） Thiosemicarbazide

1 INTRODUCTION Recently, the discoveries of antitumor effects ofinorganic complexes, especially of metal complexes,and their applications for curing cancer diseaseshave received increasing attention[1]. As a ligandwith potential S and N donors, thiosem…     

Density Functional Studies on Isonicotinato Lead(II) Complex [Pb(C5H4NCOO)2]

1 INTRODUCTION Recently, the chemistry of lead is of interest in relation to its toxicity and effects on intelligence in human populations[1~3]. The design of drugs to coun- teract the effects of lead poisoning requires estab- lishing the preferred ligands of Pb(II) and their ste- reochemistry. Consequently, synthesis of chelated- form antidotes for lead(II) ion toxicosis has attracted more and more attention, and numerous reports con- cerning experimental coordination chemistry of lead(…     

CeO2(110)表面上CO氧化反应的密度泛函理论研究

利用密度泛函理论系统研究了O2与CO在CeO2(110)表面的吸附反应行为. 研究表明, O2在洁净的CeO2(110)表面吸附热力学不利, 而在氧空位表面为强化学吸附, O2分子被活化, 可能是重要的氧化反应物种. CO在洁净的CeO2(110)表面有化学吸附与物理吸附两种构型, 前者形成二齿碳酸盐物种, 后者与表面仅存在弱的相互作用. 在氧空位表面, CO可分子吸附或形成碳酸盐物种, 相应吸附能均较低. 当表面氧空位吸附O2后(O2/Ov), CO可吸附生成碳酸盐或直接生成CO2, 与原位红外光谱结果相一致. 过渡态计算发现,O2/Ov/CeO2(110)表面的三齿碳酸盐物种经两齿、单齿过渡态脱附生成CO2. 利用扩展休克尔分子轨道理论分析了典型吸附构型的电子结构, 说明表面碳酸盐物种三个氧原子电子存在离域作用, 物理吸附的CO及生成的CO2电子结构与相应自由分子相似.     

Structural and Electron Density Studies on a Chromium(IV)-Oxo Complex [CrIV(O)(TMP)]

The electron density distribution of a chromium(IV)-oxo complex, [Cr^IV(O)(TMP)] (TMP = 5,10,15,20-tetrakis-p-methoxyphenyl porphyrin), is investigated by molecular orbital calculation. The molecular and crystal structure of the compound is studied by x-ray diffraction. It belongs to the space group 1 2, Z = 2, a = 14.979(4) Å, b = 9.752(3), c = 15.605(3) Å, β = 100.97(2)°, V = 2238(1) ų, Mo Kα radiation λ = 0.7107 Å, R = 4.9%, Rw = 3.5% for 3575 observed reflections. Cr is five-coordinated in a square pyramidal fashion with the Cr atom located 0.42 Å toward the oxo-ligand. Deformation density maps are derived from the single point molecular orbital calculation on the basis of HF and DFT(density functional theory) calculations. The accumulation of deformation density along the C-H, C-C, C-N and C-O bonds in the porphyrin ligand is well represented. The asphericity in electron density around the Cr ion is clearly demonstrated. Natural bond orbital analysis (NBO) reveals that the Cr-O_oxo is actually a triple-bond character (σ²π⁴) and the four N of pyrrole serves as a σ-donor to Cr. The Cr-N_pyrrole bond is essentially a dative bond d-Orbital populations of Cr derived from both calculations are in good agreement with each other. Planar d_π-orbital is the most populated, which is in accord with the prediction from crystal field theory. Detail bond characterization of the Cr-L, multiple bond is discussed.     

Au(111)面甲烷硫醇吸附的密度泛函理论研究

采用基于密度泛函理论的第一性原理方法和平板模型研究了CH₃SH分子在Au(111)表面的吸附构型和电子结构. 系统地计算了S原子在不同位置以不同方式吸附的系列构型, 计算结果表明, CH₃SH分子倾向于吸附在top位上, S-C键相对于Au表面法线的夹角为62°～78°|而S-H键断裂后CH₃S_H则倾向于吸附在bri-fcc位上, S-C键相对于Au(111)表面法线的夹角为49°～57°. 比较分析CH₃SH分子和CH₃S_H的吸附, 发现CH₃SH分子倾向于不解离吸附, 表面温度的提升和缺陷的出现可能促使S-H键的断裂. 通过比较S原子在独立的CH₃SH分子和吸附状态下的局域态密度, 发现S-H键断裂后S原子和表面的键合强于S-H键未断裂时S原子和表面的键合. 扫描隧道显微镜(STM)图像模拟显示了CH₃SH和CH₃S_H在Au(111)表面吸附的3个典型的STM图像.     

2-氟-5-溴吡啶分子振动光谱的密度泛涵理论研究

用密度泛函理论方法B3LYP以及6-311++G(2df,2pd)基组对2-氟-5-溴吡啶分子 的平衡几何构型进行了优化并计算了该分子的振动谐力场。使用Pulay的标度方法 对理论力场进行了标度。采用Wilson的GF矩阵方法,根据标度后的理论力场进行了 简正坐标分析,对2-氟-5-溴吡啶分子的振动基频进行了理论研究,得到了势能分 布和红外振动频率。与红外频率的实验值相比较,理论频率的均方差为24 cm~(-1) 。此外,根据振动模式的势能分布对此分子的振动基频进行了理论归属,并对前人 的指认进行了修正和补充。     

Study of the [Cr(H2O)5NO]2+ Complex via Density Functional Theory

On the basis of density functional theory, the spin ground state of chromium‐nitrosyl complex [Cr(H₂O)₅NO]²⁺ (S = 1/2) is studied via B3LYP hybrid method. Its vibrational frequencies, atomic charges, and spin densities are analyzed. The excitation energies are evaluated using the CIS method. Our calculated N‐O stretching frequency and excitation energies are in good agreement with the IR and UV‐vis data. The related Cr^I(H₂O)₆⁺, Cr^II(H₂O)₆²⁺, and Cr^III(H₂O)₆³⁺ complexes are employed as the reference compounds to determine the characteristics of the central Cr. Results indicate that the effective Cr oxidation state is close to Cr(I).     

双核Pt(Ⅳ)配合物与Guanosine-5''''-Monophosphate和Glutathione反应的核磁共振光谱研究

合成了一个新型的双核Pt(Ⅳ)配合物{[cis-Pt(NH3)2Cl(OH)2]2(4,4'-methylenedianiline)}(NO3)2(化合物1)及相应的 15N标记化合物{[cis-Pt(15NH3)2Cl(OH)2]2(4,4'-methylenedianiline)}(NO3)2(化合物15N-1).利用1H NMR和ESMS进行了结构表征,化合物15N-1的2D[1H,15N]HSQC NMR发现,该化合物在水溶液中存在同分异构体.2D[1H,15N]HSQC NMR技术跟踪了化合物15N-1与Guanosine-5'-Monophosphate(5'-GMP)和Glutathione(GSH)的反应.结果显示,5'-GMP能在0.5 h内将化合物1还原,而GSH在6 h以后才能够部分的将化合物1还原.化合物1所表现出来的反应性能将有利于提高其治疗效果和降低毒副作用.     

氢气吸附的密度泛函理论方法的基准研究

采用密度泛函理论方法对氢气吸附进行了基准研究.探讨了不同泛函方法,范德华作用及基组大小在计算中对预测氢气吸附能的影响.研究结果表明,不同泛函预测吸附能给出的偏差很大,范德华作用校正不容忽视;基组和模型尺寸影响相对较小;模型越大对基组依赖性越小;选择小的模型可以通过选择较大基组弥补计算的误差.     

Pt（111）和Pt3Ni（111）表面上CO催化氧化反应的密度泛函理论研究

采用密度泛函理论,对Pt(111)和Pt3Ni(111)表面上CO和O的单独吸附、共吸附以及CO的氧化反应进行了系统的研究. 结果表明, Pt3Ni(111)表面上CO的吸附弱于Pt(111)表面, O的吸附明显强于Pt(111)表面. 两个表面表现出相似的CO催化氧化活性. 表面Ni的存在不但稳定了O的吸附,同时也降低了过渡态O的能量.     

含氮ZSM-5分子筛骨架中氮取代位置的密度泛函计算

运用Gaussian 98程序包, 采用密度泛函理论B3LYP方法, 基于ZSM-5分子筛的8T模型, 分别通过6-31G, 6-31G(d)和6-311G(d,p)基组计算了ZSM-5分子筛中氮原子取代前后各O原子和各N原子的能量, 从而得到各O原子与各N原子在骨架中的稳定性及其对氮化取代反应的影响. 计算结果表明, N原子在骨架中的稳定性对氮取代反应的影响较大. ZSM-5分子筛晶体结构中与B酸位处于同一个四面体的O11位置, 为氮原子的最佳取代位置, 因此氮化后分子筛表面的B酸强度得到较大程度的减弱.     

CN在 Pt(100)表面吸附的密度泛函研究

采用密度泛函方法,以原子簇Pt14为模拟表面,对CN自由基分子在Pt(100)表面上不同吸附位的吸附情况进行了研究.结果表明,CN分子吸附在Pt(100)面上时,通过原子C垂直吸附在表面顶位是其最佳吸附方式,CN键振动频率明显发生蓝移,与实验事实相吻合;而在桥位及四方穴位吸附时CN键振动频率均发生红移.吸附前后,CN分子的σ、π电子与底物间的电荷转移的差异决定了CN键振动频率的不同变化.     

5-氟胞嘧啶互变异构的密度泛函理论计算

采用BH-HLYP/6-311＋G**方法对10种气相和水相中可能存在的5-氟胞嘧啶互变异构体进行了几何全优化, 并计算出它们的总能量和吉布斯自由能. Onsager反应场溶剂模型用于水相的计算. 计算结果表明, 5-氟胞嘧啶在气相中主要以烯醇式-氨基式形式存在, 在水相中主要以酮式-氨基式形式存在. 溶剂化自由能与异构体的气相偶极矩存在相关性．进一步求得互变异构化以及构象异构化和顺反异构化的过渡态, 探讨异构化过程中的几何结构和能量的变化.     

Ethanol Oxidation Reaction Mechanism on Gold Nanowires from Density Functional Theory

Thin gold nanowires (NWs) are materials that could be used as support in different chemical reactions. Using density functional theory (DFT) it was shown that NWs that form linear atomic chains (LACs) are suitable for stimulating chemical reactions. To this end, the oxidation reaction of ethanol supported on the LACs of Au−NWs was investigated. Two types of LACs were used for the study, one pure and the other with an oxygen impurity. The results showed that the oxygen atom in the LAC fulfills important functions throughout the reaction pathway. Before the chemical reaction, it was observed that the LAC with impurity gains structural stability, that is, the oxygen acts as an anchor for the gold atoms in the LAC. In addition, the LAC was shown to be sensitive to disturbances in its vicinity, which modifies its nucleophilic character. During the chemical reaction, the oxidation of ethanol occurs through two different reaction paths and in two stages, both producing acetaldehyde (CH₃CHO). The different reaction pathways are a consequence of the presence of oxygen in the LAC (oxygen conditions the formation of reaction intermediates). In addition, the oxygen in the LAC also modifies the kinetic behavior in both reaction stages. It was observed that, by introducing an oxygen impurity in the LAC, the activation energy barriers decrease ∼69 % and ∼97 % in the first and second reaction stages, respectively.     

MCM-22分子筛酸性的DFT理论计算研究

本文利用量子力学中的密度泛函理论(DFT)计算，研究了MCM-22分子筛上骨架Al在8个不同的T位的分布和Br?nsted酸的落位及强度。所有计算基于分子筛的8T簇模型 (H₃SiO)₃Si-O(H)-T(OSiH₃)₃(T=Si，Al)，采用DFT的BLYP方法，所有原子均应用DNP基组。通过计算(Al，H)/Si替代能和质子亲和势，得出推论：MCM-22分子筛中骨架Al的最有利落位在T1，T4，T3和T8位。而形成Br?nsted-酸的最可能的位置为Al1-O3-Si4，Al4-O3-Si1，Al3-O11-Si2和Al8-O10-Si2桥基。Al1-O3H-Si4和Al4-O3H-Si1位的酸性强度接近，Al3-O11H-Si2和Al8-O10H-Si2位的酸性分别略低于和略高于前两个酸位。通过计算模板剂分子六次甲基亚胺(HMI)与B-酸中心的相互作用，进一步探讨了HMI对分子筛中Al落位的靶向作用。     

A Photoactivatable Platinum(IV) Complex Targeting Genomic DNA and Histone Deacetylases

We report toxic effects of a photoactivatable platinum(IV) complex conjugated with suberoyl‐bis‐hydroxamic acid in tumor cells. The conjugate exerts, after photoactivation, two functions: activity as both a platinum(II) anticancer drug and histone deacetylase (HDAC) inhibitor in cancer cells. This approach relies on the use of a Pt^IV pro‐drug, acting by two independent mechanisms of biological action in a cooperative manner, which can be selectively photoactivated to a cytotoxic species in and around a tumor, thereby increasing selectivity towards cancer cells. These results suggest that this strategy is a valuable route to design new platinum agents with higher efficacy for photodynamic anticancer chemotherapy.